Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755528Ab3I3OtH (ORCPT ); Mon, 30 Sep 2013 10:49:07 -0400 Received: from perceval.ideasonboard.com ([95.142.166.194]:52546 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753941Ab3I3OtF (ORCPT ); Mon, 30 Sep 2013 10:49:05 -0400 From: Laurent Pinchart To: VDR User Cc: Adam Lee , Linux Kernel Mailing List , Matthew Garrett , Mauro Carvalho Chehab , "open list:USB VIDEO CLASS" Subject: Re: [PATCH] Revert "V4L/DVB: uvc: Enable USB autosuspend by default on uvcvideo" Date: Mon, 30 Sep 2013 16:49:10 +0200 Message-ID: <2929853.aH7hYkoiDo@avalon> User-Agent: KMail/4.10.5 (Linux/3.8.13-gentoo; KDE/4.10.5; x86_64; ; ) In-Reply-To: References: <1366790239-838-1-git-send-email-adam.lee@canonical.com> <1657156.ZjLeh8FSxj@avalon> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1832 Lines: 42 Hi, On Tuesday 24 September 2013 08:55:19 VDR User wrote: > On Tue, Sep 24, 2013 at 4:34 AM, Laurent Pinchart wrote: > > I've discussed this issue during LPC last week, and I still believe we > > should enable auto-suspend. The feature really saves power, without it my > > C910 Logitech webcam gets hot even when unused. > > > > If we disable auto-suspend by default and enable it from userspace only a > > handful of devices will get auto-suspended. Unless we can get distros to > > automatically test auto-suspend on unknown webcam models and report the > > results to update a central data base (which would grow much bigger than a > > quirks list in the driver in my opinion), disabling auto-suspend would be > > a serious regression. > > Setting defaults which knowingly cause problems is a horrible idea. Just > because it works for you and your setup is no justification to force it upon > everyone. This is certainly a feature that, if wanted, can be enabled by the > user. It's not just my setup, auto-suspend works for the vast majority of webcams. It has been enabled three years ago, with a report that Fedora had enabled it by carrying a kernel patch for a while, without any user complaint. > I don't see any reasonable argument against letting the user enable it if > he/she wants it. USB autosuspend is an important power saving feature. I would be fine with enabling it in userspace if we could find a reasonable, cross-distro way to create, maintain and distribute the list of devices that support USB autosuspend properly. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/